/*
 * 通配符使用
 */
class Info<T> {
    private T key;

    public void setKey(T key) {
        this.key = key;
    }

    public T getKey() {
        return key;
    }

    @Override
    public String toString() {
        return this.getKey().toString();
    }
}

public class GenericDemo4 {
    public static void main(String[] args) {
        Info<Integer> info = new Info<Integer>();
        info.setKey(1234321);
        tell(info);
    }

    /* 通配符 : ?
    * */
    public static void tell(Info<?> info) {
        System.out.println(info);
    }
}
